Conventionally, for instance, in a longitudinal flaskless molding line (see, e.g., Patent Literature 1), a pusher of a molding machine pushes out molds that are made therefrom such that the molds are intermittently conveyed on the line. Because such a high-speed molding line should inevitably provide a high-speed pouring, a stopper-type pouring machine (see, e.g., Patent Literature 2) that may be readily adapted to the high-speed pouring is often employed. In this stopper-type pouring machine, the stopper (stopper rod) opens and closes a pouring nozzle that is mounted on the bottom of a ladle. Molten metal is stored in the ladle when the pouring nozzle is closed by means of the stopper. The pouring nozzle opens by means of the stopper to pour the molten metal into a sprue of a mold under the pouring nozzle.